220 



KNOWLEDGE 



[October 1, 1895. 



where evaporation is greatest. TLie westerly equatorial 

 flow is not directly due to the impelling force of the trade- 

 winds, for if all friction between the sea-surface and the 

 trade-winds were removed, the general oceanic circulation 

 would continue much as it does now. It is possible that 

 the angular velocity of the sea-surface is diminished by the 

 moon's unequal attraction to a greater degree than is the 

 velocity of the solid globe. If the velocity of rotation of 

 the ocean has been diminished one-thousandth part more 

 than that of the earth, it would account for the westerly 

 motion of the ocean surface in equatorial regions. Wind 

 is not necessarily the cause of the current observed along 

 with it. As local disturbances of equilibrium are every- 

 where occurring at the surface of the ocean, if the local 

 current tending to restore equilibrium flows more or less 

 with the wind, it will do so as a surface current ; if it has 

 to force its way against the wind, it will flow as a sub- 

 surface current. The author urged owners of large yachts 

 to combine to make thorough observations of currents on 

 a particular region at particular times. 



Prof. W. Libbey, D.Sc, read a paper on " The relations of 

 the Gulf Stream and the Labrador Current," which are 

 especially important as bearing upon the migrations of 

 schools of fish. The region off the southern coast of New 

 England was chosen for this inquiry, and the 50° F. curve 

 of temperature was a most interesting one. The upper and 

 lower waters were dealt with separately. Uppei- : — The 

 boundary between the cold and warm waters at the surface 

 is very seldom a vertical straight line. The winds sway 

 the surface waters of these currents one way or another, 

 it may be for miles, just as they may retard or reinforce 

 them in their general direction. The winds here are of 

 two classes, south-easterly and north-westerly. The 

 tendency of the former is to drive the surface warmer water 

 towards the coast, and above the colder Labrador current, 

 while that of the latter will have the opposite efl'ect. 

 After allowance is made for other factors, the winds are 

 the most active causes of the variations here. By the 

 accumulation of variations in one direction, it is possible 

 that the boundary may be carried far from its normal 

 position. Loiret- portion: — Though the lower waters are 

 affected mainly by the larger factors in oceanic movements, 

 yet the cumulative effect of minor impulses will be felt by 

 them, but the changes in the lower waters will be less rapid 

 than in the upper. Neither the 45° line nor the GO^ line 

 showed any great deflections, thus apparently indicating 

 that they are usually well within the boundaries of each 

 of the main bodies of their respective currents. In the 

 spring of 1882, the sea from Cape May to Nantucket 

 was covered with millions of the tile-fish [LopholatHm 

 chamieleonticeps), dead or dying, and this fish has not since 

 been found there, although the author caught it south of 

 Martha's Vineyard. This is accounted for by changes of 

 temperature affecting the sea bottom in certain areas to 

 the injury of a fish probably tropical in origin. The dead 

 bodies of the fish came to the surface in a long, crescent- 

 like curve, which followed the line of the edge of the 

 continental platform between Cape May and Nantucket. 



' ' Geographical Societies and Oceanography ' ' was the title 

 of a paper by Prof. J. Thoulet, in which societies were 

 urged to pay greater attention to the geography of their 

 respective regions, and, more particularly, societies in 

 towns near the sea were recommended to undertake the 

 compilation of information relating to the oceanography 

 of their adjacent seas. 



Prof. Otto Pettersson described the details of a proposed 

 scheme for an international hydrographic survey of the 

 North Atlantic, the North Sea, and the Baltic, which he, 

 in conjunction with Dr. G. Ekman, had drawn up ; and 



Mr. H. N. Dickson read a paper on the circulation of waters 

 on the east coast of Great Britain, which gave the results 

 of the work done by the Jackal expedition of the 

 Fishery Board of Scotland, despatched in 1893 in con- 

 nection with Prof. Pettersson's scheme. The fact that 

 water of the highest salinity is not found at the surface 

 near the eastern coasts of Great Britain points to an 

 extremely complex process of mixture taking place at 

 lower levels. 



A paper on the counter-current, "El Nino,'' on the coast 

 of Northern Peru, was read by Senor F. A. Pezet. Great 

 uncertainty exists as to the cause or causes of this current, 

 which exercises a great influence on the climatic conditions 

 of the coast of Northern Peru, and it seems certain that 

 the great rainfalls in the otherwise rainless regions of Peru 

 have been due to the current. A closer investigation of 

 the subject is, therefore, most desirable. 



AFRICA. 



Sir .John Kirk's paper was on " The Suitability of 

 Tropical Africa for Development by White Eaces, or under 

 their Superintendence." Though dealing with the whole 

 of Tropical Africa, the paper was more especially devoted 

 to those portions occupied by England, with the object of 

 inviting discussion, and considered (1) the possibilities of 

 colonization proper ; (2) the establishment of European 

 settlements in places permitting of temporary residence, 

 or more permanent residence by a very limited number of 

 Europeans ; (3) the means whereby the native races may 

 themselves be taught to aid in the development of the 

 country. The introduction of steam-power and improved 

 firearms, and the opening of the Suez Canal, had 

 reversed the causes that led to the seclusion of Africa — • 

 internal misrule, the slave-trade, an inhospitable coast, 

 absence of ports, exposure to adverse winds and ocean 

 currents, and a bad climate — from which the Arabs, 

 Persians, and Indians had an advantage. The Sahara in 

 the north and distance in the south also were adverse, but 

 the time has now come for Europe to open up Africa, and 

 by modern agencies to develop it and teach the negro to 

 assist in its development. Five conditions are necessary 

 for success, viz. : (1) the climate must approximate to that 

 of countries already settled by Europe ; (2) aggravated 

 malaria must be absent ; (3) the country must be capable 

 of supporting Europeans, and must also ofier additional 

 attractions ; (-1) these conditions must extend over an 

 adequate area, so that the colony may be sufficiently large 

 for self-defence, etc. ; (5), a rapid means of transit through 

 the unhealthy zone must be found. All maritime zones, and 

 districts below five thousand feet elevation, are useless for 

 colonization, but in the central plateaux the climate 

 compares favourably with that of countries already settled 

 by the white races. Early unfavourable experience is no 

 criterion, as original conditions can be greatly improved 

 by the resources of civilization. The healthy plateaux are 

 fertile. On the other hand, healthy districts are sometimes 

 rendered unsuitable by being broken up by intervening 

 belts of malarial country or river valleys, but steamers 

 and railways will give rapid access to the healthy areas. 

 The suitable localities are few. All West Africa is im- 

 possible of colonization, except German South-West Africa, 

 which probably has a good climate and minerals but lacks 

 harbours. Matabelelaud, and probably the high plateau west 

 of Nyassa and Batokaland, fulfil the desired conditions. 

 Masailand, with a railway, and Abyssinia, are the only 

 other possible districts. Settlement apart from coloniza- 

 tion is, however, everywhere possible, with periodic change 

 to Europe and hill-stations. The increase of the native 

 races will be a danger that must be guarded against. 

 Small colonies of British Indians will afford object-lessons 



